Wiring for XLR input on unbalanced amp - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 16th April 2007, 03:13 AM   #1
Arx is offline Arx  Canada
diyAudio Member
Join Date: Aug 2003
Location: North Vancouver, B.C.
Default Wiring for XLR input on unbalanced amp

I'm building a fairly standard chipamp, but am using xlr connectors for inputs.

I haven't got the chip wired in a balanced topology, so what I'm wondering is which pins of the input I should wire to where?
Should I short the inverting input to ground, or would this create problems if I were to plug in a balanced preamp?

  Reply With Quote
Old 16th April 2007, 04:32 AM   #2
BWRX is offline BWRX  United States
diyAudio Moderator Emeritus
Join Date: Jan 2005
Location: Pennsylvania
Hi Nick.

The best solution would be to build a differential configuration if you only plan on using balanced sources. Or you can build a differential buffer and make an instrumentation amp. Or you can transformer couple the balanced signal. If you don't want to do any of those then your best bet is to just use the noninverting and ground pins of the balanced signal. Make sure the XLR ground is grounded at the source. You can also wire in a ~600ohm resistor between the balanced outputs to provide it with a proper load. If you short either of the balanced outputs to ground you risk damaging them. Some sources can handle continuous shorts to ground but certainly not all of them are.
  Reply With Quote
Old 16th April 2007, 05:18 AM   #3
Arx is offline Arx  Canada
diyAudio Member
Join Date: Aug 2003
Location: North Vancouver, B.C.
Originally posted by BWRX
Some sources can handle continuous shorts to ground but certainly not all of them are.
Ok, cool.. That was what I would have assumed. Chances are I'll never be hooking this up to a balanced source anyways. I was just curious if there was a good way to wire it so it would work with a balanced source.

Really I just used XLRs because I hate RCA connectors.

I just shorted pins 1 and 3 together. I'll just be sure to stick with unbalanced sources.

For now it's just running off of 3 mini-plug to dual xlr cables I made up.

Digital crossover in software. I can't wait to try it.

  Reply With Quote
Old 16th April 2007, 06:57 AM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
read W.Jung, D.Self and copy Jensen pseudo balanced source.

Sites are worth reading in detail.

fig 2.4 lets you set up the power amp with an XLR input to the inverting (pin3) and non-inverting (pin2) inputs and the NFB ratio is set with the extra resistor (470r) to ground back at the source.

Note, that the capacitors in the source set the XLR input to DC blocked on both inputs. You can omit these caps at the power amp, but if you do, then any other balanced or pseudo balanced source must provide the same DC blocking or your chipamp will apply DC output offset and DC gain to the output. The electros can be bypassed with 100nF to 1uF of foil or metallised film.
regards Andrew T.
Sent from my desktop computer using a keyboard
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
ESP 101 with balanced/unbalanced input Cloth Ears Solid State 2 17th June 2006 11:12 AM
converting and unbalanced in into a balanced input joyfulstudios Parts 2 12th June 2005 12:41 AM
Converting balance to unbalanced input diyman Solid State 4 7th March 2004 09:16 PM
SOZ unbalanced input wiring question moe29 Pass Labs 10 14th January 2003 01:03 AM
Unbalanced input SOZ? paulb Pass Labs 5 27th September 2001 05:01 AM

New To Site? Need Help?

All times are GMT. The time now is 05:11 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2